linux-kernel - Re: [PATCH v2] tracing: Add NOT to filtering logic

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Date:	Tue, 2 Dec 2014 12:44:58 -0800
From:	Alexei Starovoitov <ast@...mgrid.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Theodore Ts'o" <tytso@....edu>, Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCH v2] tracing: Add NOT to filtering logic

On Tue, Dec 2, 2014 at 12:35 PM, Steven Rostedt <rostedt@...dmis.org> wrote:
>
> Ted noticed that he could not filter on an event for a bit being cleared.
> That's because the filtering logic only tests event fields with a limited
> number of comparisons which, for bit logic, only include "&", which can
> test if a bit is set, but there's no good way to see if a bit is clear.
>
> This adds a way to do: !(field & 2048)
>
> Which returns true if the bit is not set, and false otherwise.
>
> Note, currently !(field1 == 10 && field2 == 15) is not supported.
> That is, the 'not' only works for direct comparisons, not for the
> AND and OR logic.
>
> Link: http://lkml.kernel.org/r/20141202021912.GA29096@thunk.org
> Link: http://lkml.kernel.org/r/20141202120430.71979060@gandalf.local.home
>
> Suggested-by: "Theodore Ts'o" <tytso@....edu>
> Signed-off-by: Steven Rostedt <rostedt@...dmis.org>

looks good to me.
Acked-by: Alexei Starovoitov <ast@...mgrid.com>
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